Force of Nature
by Madin456
Summary: In all of their travels, battling strong opponents and hunting down danger beasts, they had forgotten one primary enemy: natural sickness. — Killugon and how sometimes the body is not as strong as the mind.


**Summary:** In all of their travels, battling strong opponents and hunting down danger beasts, they had forgotten one primary enemy: natural sickness. — Killugon and how sometimes the body is not as strong as the mind.

 **A/N:** Happy return of the manga! Have some angst.

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Force of Nature

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Whale Island is isolated far into the ocean, only accessible by boat or ship. It's known for the small fisherman's port and the rumoured Master of the Swamp that roams the waters, tamed once by a young boy in green and once by his father.

The residents have long since been living off the land. They gather wild berries from bushes to sell and choose to grow a lot of their own crops rather than importing them from the mainland. Gon, especially, has a special connection with nature, something he uses to befriend animals and acutely develop his senses.

Out in the jungles, Gon is extremely adept; it is his territory and he navigates through grassy areas with little difficulty. In large cities, however, where the environment is significantly different, it is easy enough for him to fall victim to viruses that his immune system has yet to encounter.

It doesn't take long for the island boy to get sick.

And watching Gon fight the sickness, there have only been a few times in his life that Killua has been this afraid.

.

Gon is not like Killua. He comes from a hometown surrounded by forests and the sea, and while he himself has adjusted well to the urban lifestyle since becoming a Hunter, his body constantly struggles to keep up. There are creatures that he has never seen before, germs he has never encountered, illnesses with symptoms he does not even recognize until it is too late. Vaccines he never had the chance to take.

It starts with a sore throat that is immediately dismissed, saying that, "Don't worry, I probably just caught a cold. I'll just make sure to drink lots of water!" But then the coughs come, wretched things that bends Gon's body in half, his insides churning violently as his voice turns raspy from overuse.

They decide to book a hotel, and on the first night, the brown-haired boy isn't able to get any sleep. Pain takes over his entire being, stomach aches followed by fatigue and weakened muscles in a vicious cycle that holds him a prisoner to his own body. Finally, in a last act of cruelty—or perhaps mercy—he starts to drift off, slowly but not at all peacefully.

Killua panics. They are alone, having travelled long distances with no real destination in mind, and the way Gon is trembling under the blankets, coming in and out of consciousness every few minutes, leaves the white-haired boy unable to do anything except hold his friend's hand through the aching. Gon's body burns with a fever that scorches Killua's palm when he reaches out to press a hand against his forehead.

The way the island boy is sweating beneath the sheets, how entirely too small and vulnerable he looks, sends fear into Killua's mind. He has seen sickness before, has injected poison into many of his victims as an assassin in the past, but there is something different about seeing it happen in person, seeing it happen to someone he cares deeply about. Gon has been bedridden for two days now, mind delirious and thoughts incoherent, and Killua is scared to admit: he has rarely seen someone get this sick and live through it.

And he cannot lose Gon. Gon, who met him at eye-level with a fishing rod slung over his shoulder, who shares his laughter with genuine joy, who is one of the few good things he knows when he has only known numbness before. They've come so far together, beaten strong opponents and escaped near-death situations countless times, and he _will not_ allow Gon to die from something like the flu. Something as small as a _virus._

He wants to beg for it to take him instead—just not Gon, anyone but Gon—but a disease is not a person is not something with desires nor the ability to negotiate. All it knows to do is eat, _eat_ , devour anything in its path until the hunger is satisfied.

Until Gon is dead.

.

On the third night, Killua does what he should've done the very first day: he calls Leorio.

He tells the older man everything he can, which is admittingly not much. Neither of them know the source of transmission of the illness and it's hard to pinpoint when exactly the symptoms starting appearing. The aspiring doctor lists off a bunch of possible disease names but Killua doesn't _care_ about any of the technical stuff. He just wants to know what he can _do_ to help Gon.

Pressing a hand to the other boy's neck, Killua feels for the rhythm of life. Gon's pulse is barely there, a faint little thing that Killua fears is too weak to sustain his friend's life.

As per Leorio's instructions, he wets a cloth and places it gently on Gon's head, goes out to buy a warm soup and some medicine to feed Gon, and once all that is done, he does the only thing that's left to do:

He waits.

.

When Gon wakes up, fever finally burned out, he blinks a couple of times to clear the drowsiness from his eyes. A silence stretches thin throughout the room and Killua doesn't say anything until the brown-haired boy sits up on the bed.

"Are you feeling better?" he asks, softly, wanting to reach out and touch him but scared of making Gon hurt anymore than he did these past few days.

The island boy smiles brightly. "Yup! Sorry for making you worry. I'm completely fine now!"

Killua looks at him and nods; doesn't say _you should probably take it easy for a while,_ doesn't say _you were sick pretty badly,_ doesn't say _I was scared, Gon, so scared, I thought I had lost you._

It's when they're packing up to leave the hotel that Leorio calls to check up on them and Killua gladly delivers the good news. Before hanging up, the older man yells at them to visit a clinic immediately to get up-to-date with the current vaccinations or else, _"I will personally fly over to wherever you guys are and force a needle into your arms myself, you got that?!"_ At this, both the boys groan but give their promises to the medical student.

"Thank you," Gon says once they've left the hotel, "for looking after me while I was sick."

The words take Killua by surprise because he hadn't been expecting an outward expression of gratitude. It wasn't so much that he stayed by Gon's side as he battled out the disease; it was more like he couldn't _leave_.

"Don't make me to it again, idiot."

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 **A/N:** Later, we find out that both Killua and Gon are deathly afraid of getting shots, despite being able to kill a man with no problem. They get the vaccines anyway, because Killua doesn't want to experience the fear of coming close to losing Gon ever again.


End file.
